There has been a (re)emergence of participatory modes of audience engagement in contemporary western European theatre and performance since the mid-2000s. The concern at the root of contemporary participatory performance practice is the authenticity or inauthenticity with which one constitutes and presents one’s self in contemporary digitised society. Social media technology is not inauthentic in of itself, however the wider political economy in which social media operates encourages users to participate in a way that promotes the constitution, maintenance and presentation of a consistent, static and commodifiable self. Participation in social media in the context of neoliberalism makes users vulnerable to external influence and manipulates them into disengaging with their fundamental agency while promoting an ideology of choice and self-creation. Contemporary participatory performance practice problematises this inauthentic orientation by appropriating, reflecting and critically amplifying both social media technologies and modes of participation inherent in neoliberally induced social media. Contemporary practice also provides participatory alternatives that help audiences approach selfhood from an authentic orientation, embracing individual agency, responsibility and a liminal position between internal intention and external influence. This thesis draws upon the phenomenological ontology of Martin Heidegger and Jean-Paul Sartre to investigate the question of why this has come to pass by exploring the recent changes to the way that one presents oneself and interacts with other people through online social media.